There’s a post towards the end of the thread you linked to that makes a good point. It’s a software switch and there’s probably no guarantee it’ll totally and permanently disable the z-wave radio.
I imagine the only way to be sure is to crack the enclosure open and disconnect the z-wave antenna.
Here are a couple pics of the device intervals they were required to submit to the US Federal Communications Commission to get the device approved for sale. Not sure if that helps.